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xuzq commented on HDFS-15115: ----------------------------- Thanks [~weichiu], [HDFS-11827|https://issues.apache.org/jira/browse/HDFS-11827] not solve the problem thoroughly. The following code will also throw NPE, and the bug still exist. {code:java} if (LOG.isDebugEnabled()) { // it will be used, because i set the LOG level from INFO to DEBUG by LogLevel. builder.append("\nNode ").append(NodeBase.getPath(chosenNode)) .append(" ["); } {code} > Namenode crash caused by NPE in BlockPlacementPolicyDefault when dynamically > change logger to debug > --------------------------------------------------------------------------------------------------- > > Key: HDFS-15115 > URL: https://issues.apache.org/jira/browse/HDFS-15115 > Project: Hadoop HDFS > Issue Type: Bug > Reporter: wangzhixiang > Priority: Major > Attachments: HDFS-15115.001.patch > > > To get debug info, we dynamically change the logger of > BlockPlacementPolicyDefault to debug when namenode is running. However, the > Namenode crashs. From the log, we find some NPE in > BlockPlacementPolicyDefault.chooseRandom. Because *StringBuilder builder* > will be used 4 times in BlockPlacementPolicyDefault.chooseRandom method. > While the *builder* only initializes in the first time of this method. If we > change the logger of BlockPlacementPolicyDefault to debug after the part, the > *builder* in remaining part is *NULL* and cause *NPE* -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org